1. Field of the Invention
The present invention relates to an actuating device for an active control suspension system (AGCS), and more particularly to an actuating device for an active control suspension system which is connected to one end of an assist link having the other end mounted at a knuckle provided at both ends of a sub-frame of a vehicle body and which changes a position of a mounting point of the assist link at the vehicle body.
2. Description of Related Art
Generally, a suspension system for vehicles is disposed between a vehicle body and a wheel and connects two rigid bodies by using a plurality of links. The suspension system includes a spring, a shock absorber, a trailing arm, a knuckle, and a control arm.
Such a suspension system should satisfy basic requisites as follows.
Firstly, the suspension system effectively absorbs irregular vibration generated from a road when a vehicle runs so as to provide ride comfort to passengers.
Secondly, the suspension system controls shake of the vehicle body generated by driving action of a driver and curves of the road so as to provide driving convenience.
Thirdly, the suspension system maintains vertical load applied from the road within a predetermined range so as to secure stability when the vehicle turns or brakes.
Recently, an active control suspension system (AGCS) mounted to a rear suspension has been developed. Such an AGCS changes geometry of the rear suspension for the vehicle by using an electrically operated actuator, and resultantly reduces roll steer and improves grip of a rear wheel when the vehicle turns. Therefore, handling performance of the vehicle may be greatly enhanced.
When the vehicle turns quickly, the vehicle oversteers and controllability may be deteriorated. The active control suspension system causes toe-in of the rear wheel in this case and improves control stability.
FIG. 1 is a perspective view of a conventional active control suspension system.
The conventional active control suspension system is provided with an actuator 103 in both sides of a sub-frame 101, and the actuator 103 is provided with an operating rod 105 moving reciprocally. The operating rod 105 of the actuator 103 is connected to one end of a control lever 109 which is rotatably mounted at the sub-frame 101 through a lever shaft 107.
The other end of the control lever 109 is connected to one end of an assist link 113 through a bush B. The other end of the assist link 113 is mounted at a rear portion of a knuckle 111 through a ball joint BJ. Therefore, a connecting point between the control lever 109 and the assist link 113 forms a mounting point P of the assist link 113 at the vehicle body.
The active control suspension system causes toe-in of an outboard rear wheel 115 with respect to a turning axis which bumps when the vehicle turns.
That is, if the control lever 109 rotates by an operation of the actuator 103, the mounting point P of the assist link 113 at the vehicle body moves downwardly and toe-in of the outboard rear wheel 115 with respect to the turning axis increases. Therefore, turning stability of the vehicle may be improved and stable driving performance of the vehicle may be achieved when the vehicle turns quickly, the lateral wind blows, or the vehicle changes its lane quickly.
Since the conventional active control suspension system uses the control lever 109 between the actuator 103 and the assist link 113 as power delivery means, weight and cost may be raised.
In addition, since external force is directly transmitted to the actuator 103 through the assist link 113 and the control lever 109, durability may be deteriorated.
In addition, the control lever 109 is rotated only by a driving torque of the actuator 103, and the actuator 103 should generate the driving torque corresponding to lateral force transmitted through the assist link 113 according to movements of the vehicle. Therefore, the actuator 103 of large capacity should be used and accordingly it is difficult to design a layout of the suspension system.
Since the driving torque of the actuator 103 is transmitted to the assist link 113 through the rotation of the control lever 109, a wheel tread may be changed.
In addition, since the conventional active control suspension system uses a toe control screw 117 on the assist link 113 so as to set and control an initial toe, additional manufacture and assembly processes may be added.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.